Inhibition of splicing but not cleavage at the 5' splice site by truncating human beta-globin pre-mRNA.

AUTOR(ES)

Furdon, P J

RESUMO

Human beta-globin mRNAs truncated in the second exon or in the first intron have been processed in vitro in a HeLa cell nuclear extract. Transcripts containing a fragment of the second exon as short as 53 nucleotides are efficiently spliced, whereas transcripts truncated 24 or 14 nucleotides downstream from the 3' splice site are spliced inefficiently, if at all. All of these transcripts, however, are efficiently and accurately cleaved at the 5' splice site. In contrast, RNA truncated in the first intron, 54 nucleotides upstream from the 3' splice site, is not processed at all. These findings suggest that cleavage at the 5' splice site and subsequent splicing steps--i.e., cleavage at the 3' splice site and exon ligation--need not be coupled. Anti-Sm serum inhibits the complete splicing reaction and cleavage at the 5' splice site, suggesting involvement of certain ribonucleoprotein particles in the cleavage reaction. ATP and Mg2+ are required for cleavage at the 5' splice site at concentrations similar to those for the complete splicing reaction.

Documentos Relacionados

• Antibodies to hnRNP core proteins inhibit in vitro splicing of human beta-globin pre-mRNA.
• A 5' splice-region G----C mutation in exon 1 of the human beta-globin gene inhibits pre-mRNA splicing: a mechanism for beta+-thalassemia.
• Interplay between U2 snRNP and 3' splice factor(s) for branch point selection on human beta-globin pre-mRNA.
• Short donor site sequences inserted within the intron of beta-globin pre-mRNA serve for splicing in vitro.
• Abnormal splice in a mutant human beta-globin gene not at the site of a mutation.